Hoyer (2001) presented evidence that Contia tenuis comprises two distinct species, a short-tailed species ("common sharp-tailed snake") and a long-tailed form ("forest sharp-tailed snake"). A formal taxonomic revision is in progress.

Feldman and Spicer (2002) examined mtDNA variation in populations from California and southern Oregon and identified two lineages: a north coast clade restricted to cool evergreen forests along the Pacific coast and an interior/south clade widespread throughout California. Genetic, distributional, ecological, and morphological data suggests that the two clades are distinct at the species level, but Feldman and Spicer refrained from making a formal taxonomic revision until further studies delimit the geographic distribution of each clade.

Justification:
Listed as Least Concern in view of its wide distribution, tolerance of a broad range of habitats, presumed large population, and because it is unlikely to be declining fast enough to qualify for listing in a more threatened category.

This species occurs mainly in the west of the United States, extending into extreme southwestern Canada. Its range extends from northern and central California (along the Coast Ranges south to San Luis Obispo County and the Sierra Nevada south to Tulare County) north to the Willamette Valley, Oregon, and also includes the Puget Lowland southwest of Tacoma (at least formerly) and scattered locations on the east side of the Cascades in Washington and north-central Oregon, as well as the southern end of Vancouver Island and the nearby Gulf Islands British Columbia, at elevations from sea level to around 2,010 m (6,600 feet) (Nussbaum et al. 1983, Brown et al. 1995, Leonard and Ovaska 1998, St. John 2002, Stebbins 2003). A record from near McGillivray Lake in south-central British Columbia needs confirmation (Stebbins 2003).

This species is represented by a large number of occurrences (subpopulations). Nussbaum et al. (1983) mapped about 30 collection sites in Oregon, Washington, and British Columbia. Many more sites exist in California. The adult population size is unknown but surely exceeds 10,000 and probably exceeds 100,000. This species is locally common. The extent of occurrence, area of occupancy, number of subpopulations, and population size are probably stable.

Habitat includes moist situations in pastures, meadows, oak woodlands, broken chaparral, and the edges of coniferous or hardwood forests (Stebbins 2003); also shrubby rabbitbrush-sagebrush (Weaver 2004, Herpetological Review 35: 176). The long-tailed form appears to be associated with coniferous forest habitats that are relatively cool and humid. This snake generally is found under logs, rocks, fallen branches, or other cover. It retreats underground during dry periods.